public static void BuildPackedType(System.Type unpacked, HashSet <string> activeFields, ShaderGenerator result)
{
// for each interpolator, the number of components used (up to 4 for a float4 interpolator)
List <int> packedCounts = new List <int>();
ShaderGenerator packer = new ShaderGenerator();
ShaderGenerator unpacker = new ShaderGenerator();
ShaderGenerator structEnd = new ShaderGenerator();
string unpackedStruct = unpacked.Name.ToString();
string packedStruct = "Packed" + unpacked.Name;
string packerFunction = "Pack" + unpacked.Name;
string unpackerFunction = "Unpack" + unpacked.Name;
// declare struct header:
// struct packedStruct {
result.AddShaderChunk("struct " + packedStruct + " {");
result.Indent();
// declare function headers:
// packedStruct packerFunction(unpackedStruct input)
// {
// packedStruct output;
packer.AddShaderChunk(packedStruct + " " + packerFunction + "(" + unpackedStruct + " input)");
packer.AddShaderChunk("{");
packer.Indent();
packer.AddShaderChunk(packedStruct + " output;");
// unpackedStruct unpackerFunction(packedStruct input)
// {
// unpackedStruct output;
unpacker.AddShaderChunk(unpackedStruct + " " + unpackerFunction + "(" + packedStruct + " input)");
unpacker.AddShaderChunk("{");
unpacker.Indent();
unpacker.AddShaderChunk(unpackedStruct + " output;");
// TODO: this could do a better job packing
// especially if we allowed breaking up fields across multiple interpolators (to pack them into remaining space...)
// though we would want to only do this if it improves final interpolator count, and is worth it on the target machine
foreach (FieldInfo field in unpacked.GetFields(BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public))
{
if (field.MemberType == MemberTypes.Field)
{
bool isOptional;
if (ShouldSpliceField(unpacked, field, activeFields, out isOptional))
{
string semanticString = GetFieldSemantic(field);
int floatVectorCount;
string fieldType = GetFieldType(field, out floatVectorCount);
string conditional = GetFieldConditional(field);
if ((semanticString != null) || (conditional != null) || (floatVectorCount == 0))
{
// not a packed value
if (conditional != null)
{
structEnd.AddShaderChunk("#if " + conditional);
packer.AddShaderChunk("#if " + conditional);
unpacker.AddShaderChunk("#if " + conditional);
}
structEnd.AddShaderChunk(fieldType + " " + field.Name + semanticString + "; // unpacked");
packer.AddShaderChunk("output." + field.Name + " = input." + field.Name + ";");
unpacker.AddShaderChunk("output." + field.Name + " = input." + field.Name + ";");
if (conditional != null)
{
structEnd.AddShaderChunk("#endif // " + conditional);
packer.AddShaderChunk("#endif // " + conditional);
unpacker.AddShaderChunk("#endif // " + conditional);
}
}
else
{
// pack float field
// super simple packing: use the first interpolator that has room for the whole value
int interpIndex = packedCounts.FindIndex(x => (x + floatVectorCount <= 4));
int firstChannel;
if (interpIndex < 0)
{
// allocate a new interpolator
interpIndex = packedCounts.Count;
firstChannel = 0;
packedCounts.Add(floatVectorCount);
}
else
{
// pack into existing interpolator
firstChannel = packedCounts[interpIndex];
packedCounts[interpIndex] += floatVectorCount;
}
// add code to packer and unpacker -- packed data declaration is handled later
string packedChannels = GetChannelSwizzle(firstChannel, floatVectorCount);
packer.AddShaderChunk(string.Format("output.interp{0:00}.{1} = input.{2};", interpIndex, packedChannels, field.Name));
unpacker.AddShaderChunk(string.Format("output.{0} = input.interp{1:00}.{2};", field.Name, interpIndex, packedChannels));
}
}
}
}
// add packed data declarations to struct, using the packedCounts
for (int index = 0; index < packedCounts.Count; index++)
{
int count = packedCounts[index];
result.AddShaderChunk(string.Format("{0} interp{1:00} : TEXCOORD{1}; // auto-packed", vectorTypeNames[count], index));
}
// add unpacked data declarations to struct (must be at end)
result.AddGenerator(structEnd);
// close declarations
result.Deindent();
result.AddShaderChunk("};");
packer.AddShaderChunk("return output;");
packer.Deindent();
packer.AddShaderChunk("}");
unpacker.AddShaderChunk("return output;");
unpacker.Deindent();
unpacker.AddShaderChunk("}");
// combine all of the code into the result
result.AddGenerator(packer);
result.AddGenerator(unpacker);
}